Missing stars and alien engineers
Could VASCO’s disappearing stars really be signs of aliens? We asked astrobiologist Dirk Schulze-Makuch
As an astrobiologist, how do you make predictions about the possible behaviour of advanced alien civilisations?
That is very difficult to address. If we assume these civilisations consist of individuals, they can’t be too aggressive and short-term thinking, because otherwise they would likely have become extinct. On the other hand, an advanced species must have fought itself to the top of the food chain in the past, so they can’t be too docile and amicable either. But then we also have the example of swarm intelligence in our animal world, such as in a termite or ant state, a social structure which is also followed by some mammals, such as the naked mole rat. There are probably many other possibilities, so it is best to not have any preconceptions.
If the missing stars uncovered by VASCO are linked to advanced engineering by extraterrestrials, could we be looking at signs of Dyson spheres under construction?
I don't think that would be Dyson spheres. In a paper from 2010 my former student Brooks Harrop and I showed that a Dyson sphere, as traditionally envisioned, would be physically unstable and collapse. Only modified versions could work, for example a swarm of satellites around a planet, but then those would be barely detectable. The Dyson sphere idea came up as an explanation for the dimming of Tabby's Star [the curious variable star discovered in 2015 by Tabetha S.
Boyajian and her colleagues] for which we don't have a really convincing natural explanation yet. But we have to keep in mind that we are just beginning to explore the universe with modern telescopes, thus will not be aware of many natural phenomena and processes, and VASCO is a great tool to identify those.
What other sorts of advanced activity might explain the disappearances?
This is of course extremely speculative, as we don’t know what an alien society would construct. For me something like artificial beacons for signalling over interstellar distances comes to mind, or even large generation-type starships that move from one place to another. Any kind of observed changes would be highly interesting because they would be caused by dynamic processes, either natural or artificial.
You’ve commented that if these phenomena are artificial in some way then it could help address the Fermi paradox – could you explain a bit about what that is?
The Fermi paradox may be better termed the ‘Great Silence’. Our scientific assumptions have led us to assume that there are many habitable planets in the universe, boosted by the discovery of many exoplanets, and that Earth and the natural history of life on Earth is not a totally singular event. Then life, and also technologically advanced life, should be relatively common in the universe – yet we haven't found any firm evidence of it. There are so many possible explanations for this apparent paradox that some people wrote books about it. If we were to find something that is artificial, made by an intelligent entity, then it would resolve the ancient philosophical question: are we alone? It would mean we are not… with all its implications!